When? Preferably before it leaks. ;) Of course, a contractor we once employed used the alternative sequence, waiting until we found leaks in our house before he tried making it waterproof.
– user558May 9 '12 at 14:12

@woodchips What could be the source of leaks? Where should I preemptively put waterproof membranes?
– ipavlicMay 9 '12 at 14:25

The source of leaks is from water egressing through the tile grout(generally water won't go through the tiles). Having said that my 40 year old house has no waterproofing but it has a concrete floor and rendered wall that the tiles are attached to. Because of this the amount of time water is present on the floor / walls isn't enough to let water permeate through, with with wet room plaster or cement sheet this isn't the case and water will leak through onto the frame sub-floor etc.
– UNECSMay 10 '12 at 1:50

3 Answers
3

You install your backer board, then 'paint' this on. It's basically an adhesive roll-on rubber membrane. You then tile right on top of it.

I like this better than the traditional plastic-behind-the-backer-board for two reasons 1) You can easily put holes in the plastic during construction (screw holes, for instance) and 2) the RedGard is closer to the 'wet side' of the wall, reducing the chances of water getting into the wall.

Backer board = what you are sticking the tiles to. In most cases it'll be a cement board of some sorts. You paint this particular type of membrane onto the cement board after you tape and mud the cement board. You then apply tiles on top of that. You'd have to do the same for the shower floor, though for shower floors, I'd recommend Kerdi products: schluter.com/143.aspx
– DA01May 9 '12 at 21:49

I apologize once again for my lack of experience - in my country the walls are most likely either concrete or brick, and they are smoothed with a limestone-cement compound (mortar/plaster?) - see e.g. webgradnja.hr/clanci/unutarnja-zbuka/135
– ipavlicMay 10 '12 at 7:01

As DA01 said Always use wetseal, considering how much it costs it is a worth while investment

Install the wall sheeting (we usually use villa-board which is a cement fibre board)

Set the joints on the wall sheeting, fill any gaps between the wall and floor with silicon

After all the sheets are set and dry

Apply 1 coat of wetseal, for bathrooms in my state we seal the whole bathroom floor and up the wall 150mm where there is no splash areas and up the wall to a min of 2m in the shower

Use a fibre wetseal joint tape in all corners eg where the wall and floor meet and where walls meet, this should be install why wetseal is still wet and then wetseal should be re -applied to just the wetseal tape.

After 24hrs and wetseal is dry reapply another coat over all the area you have already covered

You can also get a professional to do this for you. Having a good wet seal job is very important for the longevity of your bathroom

While a good video, it's primarily focused on why you shouldn't tile onto sheetrock--though the examples at the end of the water damage are good (as is the Kerdi product)
– DA01May 9 '12 at 21:51

It basically tells you to waterproof the whole thing, andwhere to put that membrane. This is the information you were asking for. So how does that not give you what you need?
– user558May 9 '12 at 23:46

a) I'm not the one asking. b) like I said, the kerdi product example is good.
– DA01May 9 '12 at 23:51